I have tried calling several times. My HR21 is getting replace, the Hard Drive went bad. The order on the web site says HR20.. despite my calling several time they cannot guarantee that I will get at least a HR21, which is the black receiver. I'd rather have a HR24, but every time I call its the same answer. "We can't control what ships out".. Any tricks I need to know about to make sure the model that I want ships?